Eva Rausing, who was found dead in July at the London home she shared with her husband, an heir to the TetraPak fortune, had passed on information about the unsolved 1986 murder of Swedish prime minister Olof Palme, Swedish prosecutors have revealed.

Scotland Yard confirmed on Tuesday night that it had given information to authorities in Sweden, where investigators are now reported as wanting to question Hans Kristian Rausing as a possible witness about the information his wife claimed to have obtained.

A Swedish author who has written two books on the Palme killing said Mrs Rausing first contacted him in June 2011. She claimed she had learned that Palme had been killed by an entrepreneur who feared the politician was a threat to his business.

The author, Gunnar Wall, said he had engaged in email correspondence with Rausing, who told him she had written to the businessman on three occasions about the allegations. In one email to Wall she wrote: "Don't forget to investigate if I should suddenly die! Just joking, I hope."

Wall told the Guardian: "When her emails stopped, I did not think too much about it, until I heard that she had died in circumstances that were unclear."

"She also told me that she was going to inform the prosectors in Sweden and it seemed like she had some arrangement to meet them."

Kerstin Skarp, Sweden's deputy prosecutor general, said: "I can confirm that Eva Rausing contacted the Palme investigators and that we have received information from the British authorities. I cannot disclose any other information about the status of the investigation."

A Scotland Yard spokesman said: "We are in the possession of information that we have sent on to the Swedish authorities."

Palme was shot by a single assailant in central Stockholm on the evening of 28 February 1986, while walking home from the cinema with his wife Lisbeth.

A Social Democrat, he was a strong critic of the Vietnam war, earning Washington's wrath, was a mediator to end the Iran-Iraq war, and was active in the South African anti-apartheid struggle.

Palme's wife identified the gunman as Christer Pettersson, a petty criminal, and he was given a life sentence by a district court. However, the appeal court later ruled that her eyewitness account was not credible and released him. Pettersson later confessed to a newspaper, only to retract his statements, and died in 2004.

Other suspects have included Kurdish militantsand the South African and Yugoslav secret services.